A mobile robot has been proposed which has a traveling device, a travel control means, various sensors and a working device, and which automatically performs various working operations while traveling or after moving to a destination position. For example, a mobile cleaning robot is a robot for performing a cleaning function as one of the working functions, having cleaning means such as suction nozzle and a brush provided on a main body bottom surface, drive and steering means provided as moving functions, obstruction detection means for detecting obstructions such as walls, pillars, pieces of furniture and office machines, and position recognition means for recognizing the self-position. While obstructions such as surrounding walls and pillars in a cleaning place are being detected with the obstruction detection means, the self-position is recognized by the position recognition means and travels are made in a predetermined cleaning are to perform predetermined cleaning operations.
A mobile cleaner has been proposed (Patent Document 1) which has a plurality of optical travel distance sensors which detect movement distances in two dimensions from changes between optical images of a floor surface, a movement amount detection section which detects movement distances in two dimensions and a turning angle through which a cleaner main body has been moved on the basis of the movement distances in two dimensions detected with the sensors, and a movement control section which controls the movement of the cleaner main body on the basis of the detected movement distances in two dimensions and turning angle. The mobile cleaner is designed to accurately control the robot body by detecting the movement distances and turning angle with high accuracy. Patent Document 1: Japanese Patent Laid-Open Publication No. 2003-180586 (paragraphs [0036] to [0039], FIGS. 1 to 5).
A plurality of optical displacement sensor units must be provided in this conventional mobile vehicle. This is a cause of an increase in cost. It is important to reduce the size of the main body in the case of movement in a room of an ordinary house for example, while there is a need to prepare a space for providing a plurality of sensors. A rotational speed sensor for detecting the amount of rotation of wheels is provided as a means for measuring the distance through which the mobile vehicle moves. However, the rotational speed sensor is a restriction on the position and space for placement of a wheel system including wheels, and is a cause of hindrance to the reduction in size of the mobile vehicle.
In a mobile vehicle having moving means for moving a main body, a displacement sensor provided on the main body, and movement control means for controlling the moving means on the basis of a detected value detected by the displacement sensor, there is a subject to be solved that is to enable detection of the distance of forward/backward rectilinear movement and the in place turning angle of the mobile vehicle by means of one displacement sensor.